Micrometric attachment for combination squares



F. ROTHE MICROMETIC ATTACHMENT FOB COMBINATION SQUARES,

June 17, 1941. T

Filed June 11, 1940 INVENTOR ATTORNEY v Patented June 17, 1941 MIC-ROMETRIC ATTACHMENT FOR COMBI- NATION SQUARES Frank Rothe, Garfield, N. J.

Application June 11, 1940, Serial No. 339,879

2 Claims.

This invention relates to mechanics tools, more particularly to combination squares, consisting of a graduated blade having one or more adjustable heads slidable therealong and provided with means to retain them fixed when in adjusted position.

Such tools are commonly in use in machine shops and factories, serving their purpose satisfactorily, but are not adapted for accuracy and making close measurements such as are often required.

It is therefore the purpose of the present invention to provide simple attachments whereby measurements may be made with precision, limited in length only by the length of the blade on which they are mounted.

A further feature is in the provision of micrometric attachments for combination squares, settable by gages of known accurate length, whereby a correct reading is obtained, wholly irrespective of graduations on the blade of the square.

Another purpose is to produce simple, inexpensive means whereby a combination square may be readily transformed into a measuring instrument for obtaining exact results.

These advantageous aims are accomplished by the novel and entirely practical construction, combination and arrangement of parts hereinafter described and illustrated in the accompanying drawing, constituting a component of this disclosure, and in which:

Figure 1 is a side elevational view of an embodiment of the invention, showing its application.

Figure 2 is a top plan view of the anvil block.

Figure 3 is a sectional view taken on line 3-3 of Figure 2.

Figure 4 is a side elevational view of the micrometer head mounting.

Figure 5 is a partial edge, partial sectional view of the same.

Figure 6 is an end view thereof.

Referring in greater detail to the several views, Figure 1 shows a common form of combination square, the same consisting of a blade or rule l5, which is usually provided with graduations l6, either English or metric, and having in one side, intermediate its width, a channel I? extending throughout its entire length.

Slidably mounted on one edge of the blade is a head 23, slotted to closely straddle the sides of the blade, to which it may be adjustably secured by the clamp nut 2|.

One of the faces of the head is finished to extend outwardly at a right angle from the blade and is provided with opposed outstanding edges 22 arranged in parallel; this head may be furnished with a level and scratch point, all parts being of the usual, well known construction.

A bracket 25 is shaped to engage the face and edges 22 of the head and provided with clamp screws 26 to bind against the rear surfaces of its edges, retaining the bracket rigidly thereon; extending oppositely outward is a socket 21 adapted to contain a hardened steel ball 28, drawn by the screws against the face 22 to project centrally outward.

A slide 30 is movable along the blade IE to which it may be firmly secured, in any adjusted position, by a clamp nut 3|, engaged on a bolt 32, having an oifset head movable in the channel H; a right angled arm 33, formed with the slide, is similarly provided with a clamp nut 34 engaging a bolt 35 having an offset head 36.

A bar 40 of rectangular cross section, but having an angular rear edge 44 to fit the arm, is formed with a notch 4| to engage the head 36; in the upper enlarged portion 42 of the bar is a cylindrical opening 43 adapted to receive the front end of a micrometer stem 45.

This stem extends from an enlarged circular boss 46, adjacent a graduated barrel 41, around which the graduated sleeve 48 is rotatable in moving the spindle 49 through the barrel; the micrometer elements, like the blade and head, not being part of the invention.

The stem 45 is clamped in the bore 43 by a wedge plug 50, drawn into contact by a screw 52 threaded into the bar enlargement-r42.

In operation, the micrometer being fixed in the bar 40 and the bar clamped to the arm 33, the ball 28 is adjusted to aline with the spindle 49; thereafter a gage rod (not shown) of definite length is entered between the ball 28 and spindle 49, the micrometer set at some known point and the slide 30 adjusted along the blade.

Obviously measurements may be taken of work parts entered between the ball and spindle, and the lengths of such work parts determined by plus or minus readings of the micrometer from its setting.

The limit of length of work part is dependent only on the length of the blade, and the accuracy of the implement is limited only by the perfection of the micrometer, while the cost of the appliance is inconsiderable as compared with a measuring tool of equal efiiciency.

I claim:

1. In a measuring tool having a blade and a pair of heads each adjustable therealong, one of said heads presenting a face at a right angle to the blade and provided with opposed outwardly extending lateral edges, a bracket adjustable along said face and edges towards and from said blade, a ball held in said bracket to extend outwardly therebeyond, a bar adjustably clamped to the other of said heads, and a micrometer removably attached to said bar, said micrometer having its spindle directed towards and in register with 10 said ball.

FRANK ROTHE. 

